Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D7/00—Steering linkage; Stub axles or their mountings
  • B62D7/18—Steering knuckles; King pins
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D21/00—Understructures, i.e. chassis frame on which a vehicle body may be mounted
  • B62D21/18—Understructures, i.e. chassis frame on which a vehicle body may be mounted characterised by the vehicle type and not provided for in groups B62D21/02 - B62D21/17
  • B62D21/183—Understructures, i.e. chassis frame on which a vehicle body may be mounted characterised by the vehicle type and not provided for in groups B62D21/02 - B62D21/17 specially adapted for sports vehicles, e.g. race, dune buggies, go-karts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62K—CYCLES; CYCLE FRAMES; CYCLE STEERING DEVICES; RIDER-OPERATED TERMINAL CONTROLS SPECIALLY ADAPTED FOR CYCLES; CYCLE AXLE SUSPENSIONS; CYCLE SIDECARS, FORECARS, OR THE LIKE
  • B62K5/00—Cycles with handlebars, equipped with three or more main road wheels
  • B62K5/08—Cycles with handlebars, equipped with three or more main road wheels with steering devices acting on two or more wheels

Definitions

• the field of the invention is that of karts.
• the invention applies in particular to the field of competition karts, but also finds applications on all types of karts, and in particular leisure karts, for example rental karts.
• the invention relates to improving the efficiency and / or the comfort of piloting.
• FIG. 1 schematically illustrates a kart.
• a kart has a tubular frame 11, carrying in particular an engine, a seat 12 and a steering, having a steering wheel 13 controlling the front steered wheels 14. These front wheels are each mounted on a spindle, movable in rotation relative to the chassis. .
• the chassis carries two steering knuckle assemblies, an example of which is shown in Figure 2. These steering knuckle assemblies, also called for simplicity steering knuckles, (usually placed in the front, one on the right and one on the left) are essential elements for the operation of the karts. They have two main functions:
• the wheel axle 23 a part which supports the wheel.
• the axle 23 is firmly fixed to the articulation 21;
• the rocket arm 24 an element operated by the steering wheel making it possible to orient the axle, and therefore the front wheels in the desired direction.
• the axes 15 of the steering rocket pivots of the karts are not oriented vertically.
• the angle a formed by the axis of the pivot with the vertical measured in this longitudinal plane is commonly called the caster angle. 10 ° to 30 °, in particular 12 ° to 22 °, of the caster angle are values frequently used in the field of karting.
• the karts of the prior art systematically use a rocket geometry in which the axis of the pivot 25 and the axis of the wheel axle 26 are contained in the same plane 27. They are therefore intersecting.
• the invention relates to a kart comprising a tubular frame carrying two steered wheels each mounted on a steering knuckle connected to said frame by means of a yoke in which a pivot moves in rotation, said knuckle defining a knuckle axis. substantially horizontal and said pivot defining a pivot axis inclined towards the rear of said kart and forming a caster angle with respect to the vertical of between 10 and 30 °, allowing, in a curve, a deformation of said tubular frame, and therefore to lift or relieve a rear wheel.
• said spindle axis and said pivot axis are not intersecting, the position of said spindle axis being chosen so as to adapt the force to be applied to the flywheel in a curve.
• a kart it is desirable for a kart to be directional, for sporty and pleasant driving.
• the inventors have observed that, in a way that is not obvious in the field of karting, a modification of the position of the rocket axis allows a simple and effective adjustment of the liveliness of the kart:
• the rocket axis can be moved forward; if the kart is too light and "stings" in the bends, we can move the rocket axis backwards.
• a kart does not have a suspension, and that it is its deformable tubular frame which makes it possible to lift a rear wheel to make it spin in a curve or in a turn, and that this is made possible by the implementation from a large hunting angle.
• This chase affects the quality and efficiency of the steering, generally by making it heavy to the point of making driving difficult.
• the invention makes it possible to overcome this drawback effectively, the position of the rocket axis being chosen so as to adapt the force to be applied to the steering wheel in a curve, to offer an effective compromise between piloting precision and piloting comfort, for a given chassis.
• said king pin is offset towards the front of the kart relative to said pivot axis.
• Such a geometry makes it possible in particular to reduce the intensity of the force to be applied to the steering wheel when changing direction. In other words, this makes it possible to softer the steering, and to offer a sensation close to a power steering.
• said rocket being integral with a rocket arm connected to a steering wheel via a steering transmission
• said rocket arm may present or carry an extension towards the front of said kart, beyond said kart. pivot, on which said rocket is mounted.
• said rocket axis is offset towards the rear of the kart relative to said pivot axis.
• said rocket being integral with a rocket arm connected to a steering wheel via a steering transmission, said rocket is mounted on said rocket arm towards the rear of said kart, behind said pivot.
• the position of said spindle axis relative to said pivot axis can be adjustable between at least two adjustment positions. This makes it possible to offer the pilot a fine adjustment of the direction, between comfort and precision. It is also possible to provide several sets of rockets with different offsets of the position of the rocket axis, to allow the pilot to choose the most suitable set.
• each of said steering knuckles is integral with said pivot, said yoke being integral with said frame.
• each of said steering knuckles is integral with said yoke, said pivot being integral with said frame.
• the invention also relates to steering knuckle assemblies for kart as described above, comprising a knuckle capable of receiving a steered wheel, a pivot or a yoke connected respectively to a yoke or a pivot mounted on the frame of said kart, said rocket defining a substantially horizontal rocket axis and said pivot defining a pivot axis inclined towards the rear of said kart with respect to the vertical.
• said spindle axis and said pivot axis are not intersecting, the position of said spindle axis being chosen so as to adapt the force to be applied to the flywheel in a curve.
• FIG 1 schematically illustrates a kart
• FIG 2 shows an example of a steering rocket assembly
• FIG B illustrates the effects of lateral acceleration on a kart
• FIG 4A], FIG 4B] and [Fig 4C] illustrate the longitudinal offset of the wheels on the ground, respectively in zero offset, rear offset (case of karts) and front offset situations;
• FIG 5A], FIG 5B] and [Fig 5C] illustrate the combined effect of longitudinal offset and lateral acceleration, respectively in zero offset, rear offset (in the case of karts) and front offset situations ;
• FIG 6A and FIG 6B show respectively side and isometric views of a rocket of the prior art, exhibiting zero offset of the wheel axle;
• FIG 7A and FIG 7B show respectively side views and isometric of a rocket according to a first embodiment of the invention, having a forward offset of the wheel axis;
• FIG 8A and FIG 8B show respectively side and isometric views of a rocket according to a first embodiment of the invention, exhibiting a rearward offset of the wheel axle.
• the invention is based on the observation that the a priori of those skilled in the art of the field of karting, using deformable tubular frames and a large caster to allow this deformation, on the fact that the pivot axis and axle axis being intersecting is not a necessary condition.
• the inventors geometrically analyzed the situation and demonstrated the advantages of the invention.
• any change of direction 31 generates a lateral acceleration applied at its center of mass 32.
• This acceleration generates an illustrated force [Math 1] .
• the pilot of a vehicle rotates the wheel supports (rockets) about a roughly vertical axis (pivot axis) to impose the desired orientation on the wheels.
• the longitudinal offset of the wheels is the distance between the point of contact of the wheels 35, 36 on the ground and the pivot axis 33, 34. This distance is measured on the ground in a vertical plane in the longitudinal direction of the kart.
• FIG. 4A the point of contact of the wheel on the ground 35 coincides with the pivot axis of the rocket 33: offset 41 zero;
• FIG. 4B the point of contact of the wheel on the ground 35 is behind the pivot axis of the rocket 33: rear offset 42. This is conventionally the case with karts;
• Figure 4C the point of contact of the wheel on the ground 35 is in front of the pivot axis of the rocket 33: front offset 43.
• Such a geometry increases the intensity of the force to be applied to the steering wheel when changing direction.
• Such a geometry makes it possible to reduce the intensity of the force to be applied to the steering wheel when changing direction.
• the steering knuckles usually placed in the front, one on the right and one on the left, are essential elements for the operation of karts. They have two main duties :
• the axes of the steering knuckles of the karts are not oriented vertically. They are systematically tilted backwards in a plane longitudinal to the kart, as illustrated in figure 1.
• the angle between the pivot axis and the vertical measured in this longitudinal plane is commonly called the caster angle. 10 ° to 30 °, in particular 12 ° to 22 °, caster angle are values frequently used in the field of karting.
• This large caster allows that when the pilot turns the steering wheel, the inside front wheel is pressed into the turn, the frame deforming to lift the rear wheel on the opposite side.
• the karts of the prior art systematically use a rocket geometry in which the pivot axis and the wheel axle axis are contained in the same plane, they are intersecting.
• the very low center of gravity and the excellent performance of the kart tires mean that the lateral acceleration can reach a very high value, sometimes over 2 g.
• the consequence of the rear offset combined with a significant lateral acceleration generates in the steering wheel a return force such that this force is harmful to piloting.
• FIGS. 6A and 6B illustrate an example of a rocket assembly according to the prior art, respectively in side view and in isometric view.
• This comprises a rocket arm 61, a rocket 62 carrying in its extension a wheel axle 63 and a pivot 65.
• the pivot axis 64 is inclined backwards, at a hunting angle. a with respect to the vertical 66.
• This caster angle introduced a caster offset 612, measured on the ground 613 between the point of contact with the ground 611 of the wheel 610 and the intersection between the pivot axis and the ground .
• the axle axis 67 intersects with the pivot axis 65, at point 68.
• the invention makes it possible to adapt the force at the steering wheel to a given frame.
• FIGS. 7A and 7B illustrate a first example of a rocket assembly according to the invention, respectively in side view and in isometric view. This assembly is similar to that of Figures 6A and 6B. However, the spindle 72 is offset forwards, relative to the pivot axis 64, and is secured to an extension 711 of the spindle arm 61.
• Axle axis 67 is thus offset forward, relative to point 68. Consequently, by keeping the same caster angle a, a reduced caster offset 77 is obtained.
• FIGS. 8A and 8B illustrate a second example of a rocket assembly according to the invention, respectively in side view and in isometric view. This assembly is similar to that of Figures 6A and 6B. However, the spindle 82 is offset rearwardly, relative to the pivot axis 64, and secured to the spindle arm 61.
• axle axis 67 is thus offset rearwardly with respect to the point 68. Consequently, by keeping the same caster angle a, an increased caster offset 87 is obtained.
• the main advantages of the invention are to make piloting karts easy, less tiring and more precise.
• the installation is simple and at no additional cost compared to conventional constructions.
• the position of the rocket can be movable along the rocket arm, to allow a suitable adjustment by the pilot, for example using a rack or a worm.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transportation (AREA)
• Steering-Linkage Mechanisms And Four-Wheel Steering (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=69810896

Family Applications (1)

Country Status (3)

Citations (6)

• 2019
  • 2019-07-24 FR FR1908415A patent/FR3099126B1/fr active Active
• 2020
  • 2020-07-24 EP EP20743710.4A patent/EP4003813A1/de active Pending
  • 2020-07-24 WO PCT/EP2020/071040 patent/WO2021014015A1/fr not_active Ceased

Patent Citations (6)

Non-Patent Citations (4)

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